Abstract
The effect of an external electric field on the absorption spectrum of phenol blue in an inert, transparent rigid matrix of high dielectric strength (polystyrene) has been studied. A net band shift to the red is observed. The results may be explained by assuming that a Stark shift occurs. A shift of 12 cm.-1 at 9 X 105 v./cm. is observed on the band edge at 6500 Å., and this corresponds to an actual shift of 15 cm.-1 when an intensity change correction is applied. A method for treating data to determine true band shifts in the presence of a simultaneous change in intensity is derived. © 1964, American Chemical Society. All rights reserved.